1. Field of the Invention
This invention relates generally to a method to treat gastroesophageal reflux, and more particularly the detection and ablation and/or necrosis of gastroesophageal nerves and receptors causing transient relaxation of the lower esophageal sphincter and gastroesophageal reflux.
2. Description of Related Art
Gastroesophageal reflux disease (GERD) is a common gastroesophageal disorder in which the stomach contents are ejected into the lower esophagus due to a dysfunction of the lower esophageal sphincter (LES). These contents are highly acidic and potentially injurious to the esophagus resulting in a number of possible complications of varying medical severity. The reported incidence of GERD in the U.S. is as high as 10% of the population (Castell D O; Johnston B T: Gastroesophageal Reflux Disease: Current Strategies For Patient Management. Arch Fam Med, 5(4):221-7; (1996 April)).
Acute symptoms of GERD include heartburn, pulmonary disorders and chest pain. On a chronic basis, GERD subjects the esophagus to ulcer formation, or esophagitis and may result in more severe complications including esophageal obstruction, significant blood loss and perforation of the esophagus. Severe esophageal ulcerations occur in 20-30% of patients over age 65. Moreover, GERD causes adenocarcinoma, or cancer of the esophagus, which is increasing in incidence faster than any other cancer (Reynolds J C: Influence Of Pathophysiology, Severity, And Cost On The Medical Management Of Gastroesophageal Reflux Disease. Am J Health Syst Pharm, 53(22 Suppl 3):S5-12 (Nov. 15, 1996)).
The lower esophageal sphincter is a thickened ring of smooth muscle at the lower end of the esophagus. Normally, the LES is in a state of contraction and functions to keep the acid contents of the stomach from refluxing into the esophagus. In a healthy person the muscle relaxes only during swallowing to allow food to pass and also on average three to four times and hour in phenomenon known as transient lower esophageal sphincter relaxation (TLESR). In a person suffering from GERD, the frequency of TLSER is much higher rising as high as eight or more times and hour.
Since the resting tone of the LES is maintained by both myogenic (muscular) and neurogenic (nerve) mechanisms, some believe that abnormal or aberrant electrical signals in the lower esophageal sphincter or surrounding region of the stomach including the cardia can cause the sphincter to spontaneously relax. Such signals may cause a higher than normal frequency of TLESRs allowing acidic stomach contents to be repeatedly ejected into the esophagus and cause the complications described above. Research has shown that unnatural electrical signals in the stomach and intestine can cause reflux events in those organs (Kelly K A, et al: Duodenal-gastric Reflux and Slowed Gastric Emptying by Electrical Pacing of the Canine Duodenal Pacesetter Potential. Gastroenterology. 1977 March; 72(3):429-433). In particular, medical research has found that sites of aberrant electrical activity or electrical foci may be responsible for those signals (Karlstrom L H, et al: Ectopic Jejunal Pacemakers and Enterogastric Reflux after Roux Gastrectomy: Effect Intestinal Pacing. Surgery. 1989 September; 106(3):486-495). Similar aberrant electrical sites in the heart, which cause contractions of the heart muscle to take on life threatening patterns or dysrhythmias, can be identified and treated using mapping and ablation devices as described in U.S. Pat. No. 5,509,419. However, there is no current device or associated medical procedure available for the electrical mapping and treatment of aberrant electrical sites in the LES and stomach as a means for treating GERD.
GERD is believed to be caused by a combination of conditions that increase the presence of acid reflux in the esophagus. These conditions include transient LES relaxation, decreased LES resting tone, impaired esophageal clearance, delayed gastric emptying, decreased salivation, and impaired tissue resistance.
Current drug therapy for GERD includes histamine receptor blockers which reduce stomach acid secretion and other drugs which may completely block stomach acid. However, while pharmacologic agents may provide short term relief, they do not address the underlying cause of LES dysfunction.
Invasive procedures requiring percutaneous introduction of instrumentation into the abdomen exist for the surgical correction of GERD. One such procedure, Nissen fundoplication, involves constructing a new xe2x80x9cvalvexe2x80x9d to support the LES by wrapping the gastric fundus around the lower esophagus. Although the operation has a high rate of success, it is an open abdominal procedure with the usual risks of abdominal surgery including: postoperative infection, herniation at the operative site, internal hemorrhage and perforation of the esophagus or of the cardia. In fact, a recent 10 year, 344 patient study reported the morbidity rate for this procedure to be 17% and mortality 1% (Urschel, J D: Complications Of Antireflux Surgery, Am J Surg 166(1):68-70; (1993 July)). This rate of complication drives up both the medical cost and convalescence period for the procedure and may exclude portions of certain patient populations (e.g., the elderly and immuno-compromised).
Efforts to perform Nissen fundoplication by less invasive techniques have resulted in the development of laparoscopic Nissen fundoplication. Laparoscopic Nissen fundoplication, reported by Dallemagne et al. Surgical Laparoscopy and Endoscopy, Vol. 1, No. 3, (1991), pp. 138-43 and by Hindler et al. Surgical Laparoscopy and Endoscopy, Vol. 2, No. 3, (1992), pp. 265-272, involves essentially the same steps as Nissen fundoplication with the exception that surgical manipulation is performed through a plurality of surgical cannula introduced using trocars inserted at various positions in the abdomen.
Another attempt to perform fundoplication by a less invasive technique is reported in U.S. Pat. No. 5,088,979. In this procedure an invagination device containing a plurality of needles is inserted transorally into the esophagus with the needles in a retracted position. The needles are extended to engage the esophagus and fold the attached esophagus beyond the gastroesophageal junction. A remotely operated stapling device, introduced percutaneously through an operating channel in the stomach wall, is actuated to fasten the invaginated gastroesophageal junction to the surrounding involuted stomach wall.
Yet another attempt to perform fundoplication by a less invasive technique is reported in U.S. Pat. No. 5,676,674. In this procedure, invagination is done by a jaw-like device and fastening of the invaginated gastroesophageal junction to the fundus of the stomach is done via a transoral approach using a remotely operated fastening device, eliminating the need for an abdominal incision. However, this procedure is still traumatic to the LES and presents the postoperative risks of gastroesophageal leaks, infection and foreign body reaction, the latter two sequela resulting when foreign materials such as surgical staples are implanted in the body.
While the methods reported above are less invasive than an open Nissen fundoplication, some still involve making an incision into the abdomen and hence the increased morbidity and mortality risks and convalescence period associated with abdominal surgery. Others incur the increased risk of infection associated with placing foreign materials into the body. All involve trauma to the LES and the risk of leaks developing at the newly created gastroesophageal junction. None provide a means for detecting and treating aberrant electrical sites causing abnormal LES relaxation and gastroesophageal reflux.
There is a need to provide a method to detect and treat aberrant bioelectric activity of a sphincter and/or a stomach including myoelectric activity. There is another need to provide a method to detect and treat an electrical foci of the aberrant bioelectric activity of a sphincter and/or a stomach. There is a further need to detect and treat an electrically conductive pathway of the aberrant bioelectric activity of a sphincter and/or a stomach.
Accordingly, an object of the invention is to provide a method to diagnose and treat sphincters and/or a stomach.
Another object of the invention is to provide a method to diagnose and treat gastroesophageal reflux disease.
A further object of the invention is to provide a method to detect and treat bioelectrical activity of a sphincter and/or a stomach causing transient relaxation of the lower esophageal sphincter.
Yet another object of the invention is to provide a method to detect and treat electrically conductive pathways of bioelectrical activity in a sphincter and/or a stomach causing transient relaxation of the lower esophageal sphincter.
Still a further object of the invention is to provide a method to detect and treat a nerve pathway in a sphincter and/or a stomach causing transient relaxation of the lower esophageal sphincter.
Another object of the invention is to provide a method to detect and treat a nerve pathway in a sphincter and/or a stomach causing transient relaxation of the lower esophageal sphincter while preserving a swallowing reflex
A further object of the invention is to provide a method to detect and treat a receptor pathway in a sphincter and/or a stomach causing transient relaxation of the lower esophageal sphincter.
Yet a further object of the invention is to provide a method to create an area of electrical block to bioelectric activity of the lower esophageal sphincter and/or stomach causing transient relaxation of the lower esophageal sphincter.
These and other objects of the invention are provided in a method of treating a sphincter that provides a sphincter electropotential mapping device with at least one of a mapping electrode or a treatment electrode. The sphincter electropotential mapping device is introduced into at least a portion of the sphincter, the lower esophageal sphincter, stomach, the cardia or the fundus. Bioelectric activity causing a relaxation of the sphincter is detected and energy is delivered from either the mapping electrode or the treatment electrode to treat the bioelectric activity.
In another embodiment, a method of treating a sphincter that provides a sphincter electropotential mapping device with at least one of a mapping electrode or a treatment electrode. The sphincter electropotential mapping device is introduced into at least a portion of the sphincter, the lower esophageal sphincter, stomach, the cardia or the fundus. The sphincter, lower esophageal sphincter, stomach, cardia or fundus is stimulated to produce a transient relaxation of the sphincter. The portion of the sphincter, lower esophageal sphincter, stomach, cardia or fundus causing a relaxation of the sphincter is indentified. Energy is delivered from the sphincter electropotential mapping device to treat the portion the sphincter, lower esophageal sphincter, stomach, cardia or fundus causing the transient relaxation of the sphincter.